Template free synthesis of hierarchical porous zeolite Beta with natural kaolin clay as alumina source

摘要

A template free synthesis route was developed for the synthesis of hierarchical zeolite Beta from a natural layered aluminosilicate mineral kaolin. Detailed study on the crystallization of zeolite Beta established the optimized synthesis condition, and the synthesized hierarchical Beta zeolite was fully studied by XRD, IR, SEM, TEM, BET, NH3-TPD, Py-IR and NMR techniques. The characterization results reveal that the hierarchical Beta zeolite possesses good crystallinity, bimodal pore architecture, large surface area, big pore volume, high acid site concentration and excellent hydrothermal stability. An improved catalytic performance was achieved in hierarchical Beta zeolite for the esterification of acetic acid with benzyl alcohol, and the high activity and selectivity in this zeolite are mainly attributed to the presence of mesopores for accelerating the intraparticle diffusion rate of both reactant and product. This novel synthesis methodology provides a low-cost and environmentally-benign way for the preparation of hierarchical Beta zeolite, which could serve a sustainable platform of large-scale production of hierarchical zeolite for practical application.